Not applicable.
Not applicable.
1. Field of the Invention
This invention relates to a wet battery which needs to be topped up periodically with water or other fluid. The invention also relates to a vehicle-based water management system for use in connection with at least one unit on the vehicle which requires water for its operation.
2. Description of the Prior Art
In a motor vehicle such as a car, there are a number of units which require water for their operation and in which the supply of water must be regularly checked and topped up if necessary. These units include the radiator, the screen wash and the battery. Water is lost from the radiator due to leakage and evaporation. Water is consumed in normal use of the screen wash. Water is lost from the battery through evaporation and boiling caused by heating of the battery during its charging and discharging cycle and due to the engine temperature. In an electric vehicle, the batteries constitute the source of motive power, so it is particularly important that they be maintained in good condition at all times.
Presently, the vehicle owner must routinely inspect and refill the water supply in all these units. This is an inconvenient and irritating burden, yet damage may result or safety be compromised if the task is not done. Additionally, the water level in the cells of the or each battery should be carefully adjusted in order to optimize the performance and lifespan. This is particularly important in the case of an electric car or other vehicle. However, getting the water level right requires some skill and knowledge. Moreover, the need to check and fill each cell individually is time-consuming.
The present invention arose partly from a consideration of these problems and how they may be overcome.
In one aspect, the invention provides a wet battery comprising a plurality of cells, each cell having a respective fluid inlet, the battery having a channel which is shared by the fluid inlets for supplying fluid such as water to the cells of the battery, wherein each cell includes a float valve associated with its fluid inlet and arranged to automatically open for communication with the channel when the fluid in the cell is below a predetermined level.
According to this aspect of the invention, the procedure of maintaining the fluid level of each cell of the battery is simplified and may be automatically regulated, thereby ensuring optimum performance and lifespan.
In a preferred embodiment, the battery has an integral reservoir for temporarily holding a quantity of water. The reservoir is periodically filled manually or automatically, and then empties its content through the channel, which supplies the cells as required. Any excess water exits the channel through an overflow or may even be returned to the reservoir. According to this arrangement, the fluid level is automatically set by the valves and it is impossible to overfill the battery.
In another aspect, the invention provides a water management system on a vehicle, the system comprising water collecting means for providing a supply of water and distribution means for distributing the water from the supply to a plurality of units on the vehicle which require water for their operation.
According to this other aspect of the invention, a supply of water is always conveniently available for use by the units requiring water for their operation. The plurality of units may consist of a bank of two or more batteries in the case of an electric vehicle.
The water collecting means may be a master or central storage vessel which is filled manually. However, the water collecting means may include a source which generates water as a by-product. In one embodiment of the invention, an air-conditioning system is employed to provide the water supply. The condensate formed on the condenser of the air-conditioning system offers a reliable and clean source of water. It is also simple to collect, for example by using the conventional drip pipe of the condenser to feed the condensed water into a storage tank.
The inventor has tested the system on his own car and found that one-half of a litre of water may be collected from the car""s air-conditioner in one 30-minute city journey. This result indicates that more than a sufficient amount of water to meet the usual requirements of the radiator, screen wash and battery can be collected in this way. Thus, an adequate supply of water to those units may be guaranteed. A sample of the collected water was tested and found to have a pH value of 6.4, i.e. substantially neutral. This further demonstrates the fitness of the collected water.
The automatic supply of the collected water to the units means that the vehicle owner is spared the inconvenience of having to regularly check and top up the units. Thus, the maintenance effort is beneficially reduced and the risk of breakdown is lowered. The collected water may also be used to provide a supply of drinking or washing water within the car.